A Gainsborough man has been sentenced to 15 years in prison at Lincoln Crown Court.
Lee Schofield faced two charges of rape and five of sexual assault.
The court heard how he used alcohol to render his victim unconscious before raping her on a number of occasions.
His horrific acts came to light when DVDs were found showing graphic footage of the offences.
DC David Patten of the Lincolnshire Police Emerald Team was the investigating officer. He said, "This is one of the worst cases we have dealt with. The offending took place without the knowledge of the victim.
"When she found out about what she had been subjected to she was understandably horrified. The 15 year sentence reflects the horrendous nature of the crimes. It's reassuring to know that Schofield will be behind bars for a very long time."
Three people have appeared in court in Lincoln today, charged in connection with the murder of a Latvian man.
The body of 24-year-old Ivan Zdanovics was discovered last month following a fire at a house in Gainsborough.
Martynas Kupstys, aged 25, and Andrus Giedraitis, aged 29 were both charged with murder and perverting the course of justice. And 28-year-old Sandra Giedraityte was charged with perverting the course of justice.
Police investigating the murder of Ivans Zdanovics in Gainsborough have released an image of him. The body of the 24-year-old, who is believed to be of Latvian decent, was found at a house last Friday. At some point the fire had been on, but it was out when he was discovered.
Police are continuing to investigate the death of a twenty four year old man in Gainsborough which they are currently treating as unexplained.
Officers were called to an address on Etherington Street at around eleven o clock yesterday morning after reports that the body of a man had been found. Forensic investigations are being carried out at the scene.